Method and means for joining coaxial cables



E. L. ALFORD METHOD AND MEANS FOR JOINING COAXIAL CABLES Jan. 16; 1951Filed Dec. 29, 1945 y Q fr. D N 1a. f E RM M m QN ww NQN SQNQ. mw @w E wQN mr, m NL WA L 1 1 111 N a 1 A. f 1 Q E n .Q Q\ ON \W QM D N\\ f Q \NDN 1 1 f l a, QQ R y U B X.

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Q 1 Q Q Q Q Q Q1Q1 Q1 Q QN QN Q Q S, QQ QN E. Q Q Q 1%. Q Q Q Q mw 11e QNG WN WN QN www Q mw Q 1 i; 1 Q 1 .Q NN 1 Q 1 Q mw Q @N Q Q u 11 111 1 1111 1 11 1 1 1 1 111 11 1, 1 H111 111111 11111m 1H! 11 1 11 1 1111 1 1111 11 1111 11111 1111 11-1%11 1 1 111%1v11 111 11 11 1111 1-11 1w1111111 11 111 1 11 Q mw Q 1 111.1 111 11\ n l Qw\ Q Q 1 Q Q 11 Q 91u,on um QN uw Patented Jan. 16, 1951 UNITED STATES PATENT oFFlcE METHODAND MEANSl FoR'JoINING ooAXrAL CABLES Edward L. Alford, Chatham, N. Je.,assignor to Bell Telephone Laboratories,Incorporated, New York, N. Y., acorporation of New York Application December 2'9, 1945, Serial No.638,350

4 Claims. 1

This invention relates to `joints or splices for electrical conductorsand more particularly to a method of making joints in conductors of thecoaxial type, one or more of which may be enclosed in a suitableprotective sheath to form a cable.

The object of this invention is the provision of a method and means forsplicing coaxial conductors which will eliminate, to a large extent, theintroduction of fine metallic particles into the joint during the makingof the joint as has been experienced with the method now employed, andthe consequent short-circuiting of the conductors in the cable.

Another object of the invention is theprovision of method and means formaking joints in coaxial rconductors which will require considerablyless pressure on the component parts to form a gastight and anelectrical joint having a high conductivity.

The coaxial conductor to which the spliceof this invention isparticularly adaptable comprises, a tubular outer conductor ofrelatively thin conducting material and a centrally disposed solid innerconductor which is supported concentrically within the outer conductorand insulated therefrom by means of a plurality of suitably spaced discsor bushings of insulating material. In order to provide electromagneticshielding for the conductors, a plurality of metallic tapes arehelically Wound around the outer or tubular conductor. One or moreconductors may be enclosed in a lead sheath to form a suitable cable.

Cables employing one or more encased coaxial conductors are known ascoaxial cables amd are employed for transmitting electrical currents ofvery high frequency and it is important that the joints in theconductors be made in such a manner that the eiiiciency of the cablewill not be impaired. ,l

The present invention relates to a method and means for making joints incoaxial conductors of the above-described type and comprises, insertingin the ends of the outer conductors, in contact with the inner surfacesthereof, short metallic reenforcing sleeves, positioning on the outsideof each outer conductor over the metallic tapes and adjacent the vendsthereof a short metal sleeve, positioning over one end of the conductorand underlying the metallic tapes, a third metallic sleeve having alength somewhat longer than the other two sleeves, joining together thecentral solid conductors by means of a suitable sleeve,

locating the large sleeve over the joint of the inner conductors withits endsl overlying a substantial portion of the outer conductor and thereenforcing sleeve, positioning the small sleeves in abutting relationWith the large sleeve and then` tact with the steel tapes, to provide agas-tight joint having substantially the same electricalcharacteristics" as these of the conductors.

The inventionwill be more clearly understood from the following detaileddescription when read in connection with the following drawings ofwhich:

Fig. l is a fragmentary view, partly in section of the jointpof thisinvention in its early stage of preparation', with the centralconductors joined together, the reenforcing sleeves in place, the tapesheld in position by the rings and the small outside sleeves in placeover the ends of the outer conductor and the tapes;

Fig. 2 is a view similar to Fig. 1 except that the tapes are now inposition around the outer conductors and the sleeves have been moved inposition with the large sleeve over the joint of the inner conductorsand the small sleeves over the ends of the tapes;

Fig. Y3 is a view similar to Fig. 2 and discloses suitable means forforcing the sleeves into intimate Contact with the outer conductors andmetallic tapes to provide a completed joint; and,

Fig. 4 is a cross-sectional view taken on line 4-4 of Fig. 3 andillustrates in detail the crimp- Y ing ring for holding the metallictape in position While making the joint.

As shown in the drawing, the joint of this inventionl comprises threesleeves, namely, a large central sleeve I0 and the two small end sleevesI I and I2. The central sleeve I0 is centrally disposed over the sleeveI3, which serves to join the ends I4 and I5 of the central conductorsI6`I6 together, and embraces the outer surfaces of the ends*V I1 and I8of the outer conductors Ill-I9 for a. short distance on each end. Thesmall end `sleeves II and I2 are positioned over the ends of themetallic tapes 20 and 2|, the sleeve II engaging the ends 22 and 23andthe sleeve I2 engaging the ends 24 and25.

Located in the conductors |6-I6, a short distance from each end thereof,are the reenforcng sleeves 2S and 21. Suitable insulating discs orspacers 23 maintain the solid conductors |6-I6 centrally disposed withinthe outer conductors I9`-I9.

In making the joint of this invention, the lead sheath (not shown),which encloses the conductors to be joined, is removed some distancefrom the ends thereof in the well-known manner, to expose the coaxialconductors located therein. The ends of the conductors to be joined arepre* pared in the following manner. A suitable ring 29 is threaded overthe outside of the metallic tapes 2D and 2| of the conductor to the leftof the splice and crimped thereover some distance from the end thereof.The next step is to remove a portion of the metallic `tapes 2U 2| at theend of the conductor to expose a portion of the outer conductor I9,asshown he,draw ing, then proceed to cut and remove 'a ,Smll section ofthe outer conductor I9 leaving exposed, however, beyond the tapes and 2|and end portion Il. The removal of a portion of the outer conductor I9,exposes the solid inner conductor I6 and its associated spacer 28 whichis also removed. A portion of the conductor I6 is out off so that itprojects only a short distance beyond the end of the outer conductor I9.Thus .we have the solid or central conductor I6 projecting a shortdistance beyond Vthe end of the outer conductor ,I 9 and the outerconductor .I 9 projecting a short `distance beyond the end of themetallic .tapes 2 9 and 2|. After the above steps have been completed, areenforcing sleeve or bushing 26 is inserted in the outer conductor I9,a short distance beyond the end Il thereof and an insulating spacer 2.8is positioned in the end ofthe outer conductor I9 with its outer faceflush with the end ITI of the outer conductor I9.

With the metallic tapes 2G and 2i held in tig-ht `Contact around theouter conductor I9 by any suitable means, a small sleeve I I is threaded.thereover and positioned some distance back from 4the end .I'I of theouter vconductor i9 ywhich may be against the ring 29 as shown inFig. 1. A large sleeve Il! is positioned over the outer conductor I9 andslid under the tapes 29 and 2l a sufcient distance so that the endthereof is `slightly in back of A4the end Il of the conductor [.9 asshown in Fig. 1.

The end I8 ,of the right-hand conductor which is to be joined with theleft-hand section, here tofore described, is prepared ina similar mannerexcept that the tapes 20 and 2 I are not loosened but are held in placeby `means of clamping rings 39e-3.9 and no large sleeve is positionedthereon.

With the ends of the .conductors to be joined prepared as heretoforedescribed and with the ends .I'l and .I8 of the Aouter conductors I9.-I9 in alignment and with the ends I4 and'IS of the inner conductorsI6-II3 .directly opposite each `other and spaced apart slightly, ametallic splicing sleeve I3 is positioned over the ends thereof and,compressed thereon, as shown at 3I.-e-3l in the various vfigures, tojoin the ends I4 and I5 of the central conductors I-IG together, an insulating disc 28' is positioned over the sleeve I3 at its midpoint.

With the joint prepared as sho-wn in Fig, 1 and as described above, itis now ready for closure and as shown in Fig. 2 this is accomplished bysliding the sleeve ID over the vouter conductors IB-.I-Q so as to coverthe splice and bear against the temporary spacer 33 which in turn ispositioned against the small sleeve I2, making sure that the tapes 2Uand 2! on the left-hand conductor end are tightly wound around the outerconductor I9. The small sleeve II is slid along its length until itbears against the .end of the sleeve IIJ as shown in Fig. 2. With thesleeves IIJ, II and I2 in position as shown in Fig. 2, a length ofadhesive tape 33 is Wound around the tapes 20 and 2| adjacent the sleeveII to prevent movement thereof.

As shown in Fig. 2, the joint is now in condition for the finaloperation which is forcing the sleeves JIU., II 4and I2 in-to intimatecontact with the tapes 'and o uter conductors to `form a gastight jointhaving a high conductivity. It has been found that the rolling toolshown in Patent 1,896,512 toHayford et al. dated February 7, 1933 isparticularly adapted for use with this type of joint since it is notcumbersome to handle and can .be operated :with a minimum amount oftorque.

The vfirst step in rolling the sleeves I0, II and I2 into `intimateengagement with the tapes 20 and 2| and the ends II and I8 of the outerconductors I9.-4S, is to position the rolling tool 34 to the left of thesleeve II with the ats 35 and 36 of the rollers STI and 38 parallel. Theconductors and sleeves are 4,then positioned in the grooves 39 and 4;0Of the rollers 31 and 38 and the handle `4I iotated ,in a .clockwisedirection to ycause the vrefilers 3,9 and 3l to traverse the lsleeves asshown in Fig. 3 and compress the sleeves I9, II and I2. ine vtemperaryspacer ,3,3 may be rremoved any .time a'fitger the rolling action oj the[central sleeve jfil begins ,a5 it only serves to provide -suiiicientspace e2: '.fQr .the sleeve I9 lto expand.

'.he :tool 34 is removed-:from the cable by .rotating the vrollers 3'!and 38 until the fla-ts 36 are Vagain parallel.

While I have shown and described jherein the preferred embodiment of myinvention, it :is t0 be understood that various modifi-,cations andchanges may be made therein without departing from thespiri-t oftheinvention `and YI do not limit myself to the use of .any particular toolfor forcmetallic sleeve positioned .over the inner conducjoining meansin engagement with the outer surfaces of the outer conductors andextending over said reenforcing bushings, metallic sleeves located oneat each end of said first sleeve over said protective sheath, all ofsaid sleeves secured in position by having a force applied thereto alongthe outside surfaces thereof to establish an Y2. In combination with apair oi coaxial conductors each comprising a plurality of outerprotective metallic tapes, an outer conductor `andV an inner conductor.,of means for joining the -ends of said -conductors together whichcomprises, means-for joining the ends of the inner conductors together,metallic reenforcing bushings vlocated inside the outer conductors, ametallic sleeve positioned over the inner conductor joining means inengagement with the outer surfaces oi the outer conductors and extendingover said reeniorcing bushings, metallic sleeves located one at each endof said first sleeve in 5 contact with said metallic tapes, all. of saidsleeves secured in position by having a force applied thereto along theoutside surfaces thereof to establish an intimate contact between saidfirst sleeve and the outer-,conductors, and between said end sleeves andsaid metallic tapes,

3. In combination with a pair of coaxial conductors, each comprising anouter protective metallic sheath, a single hollow outer conductor and asolid inner conductor, of means forX joining the ends of said conductorstogether which comprises, means for joining the ends of the innerconductors together, metallic reenforcing bushings located inside theouter conductors, a metallic sleeve positioned over the inner conductorjoining means and in engagement with the outer surfaces of the outerconductors and extending over said reenforcing bushings, metallicsleeves located one at each end of said rst sleeve in contact with saidmetallic sheath, all of said sleeves secured in position by having aforce applied thereto along the outside surfaces thereof to establish anintimate contact between said first sleeve and the outer conductors, andbetween said end sleeves and said metallic sheath.

4. A method for making a joint in coaxial conductors having a solidcentral conductor, a hollow outer conductor and a layer of tape armoringover said outer conductor which comprises, removing from the ends of theconductors sufficient tape armoring to expose the outer conductor,removing a portion of the outer conductor to expose the inner conductor,inserting in the ends of the outer conductor in contact with the inner 6l surfaces thereof, short metallic reenforcing bushings, positioningover the tape armoring adjacent the ends of said outer conductor sleevemembers, positioning over one end of the outer conductor and underlyingthe armoring tapes, a third metallicsleeve, joining together the ends ofthe central conductor, locating the third sleeve over the joint of theinner conductor with its ends overlying a substantial portion of theouter conductor and said reenforcing bushings, positioning the endsleeves in abutting relationship with the ends of the third sleeve andthen subjecting the whole assembly to the compressing action of asuitable tool for forcing the third sleeve into intimate contact withthe outer surfaces of the outer conductor and the end sleeves intointimate contact with the armoring tape.

EDWARD L. ALFORD.

REFERENCES CITED The following references are of record in the le ofthis patent: v

UNITED STATES PATENTS Number Name Date 1,735,563 Deckard 1- Nov. 12,1929 2,111,651 Wentz Mar. 22, 1938 2,133,448 Harley Oct. 18, 19382,210,804 Eby Aug. 6, 1940 2,305,473 Hayford Dec. 15, 1942 FOREIGNPATENTS Number Country Date 465,417 Germany Sept. 8, 1928

